Short Communications

Efficacy of fungicides in the control of ergot (Claviceps africana) in sorghum (Sorghum bicolor) hybrid seed production

Published in: South African Journal of Plant and Soil
Volume 20, issue 3, 2003, pages: 154–156
DOI: 10.1080/02571862.2003.10634926
Author(s): N.W. McLaren,

Abstract

Ergot is a disease of unfertilized sorghum ovaries. It is particularly prevalent in seed production where losses may average 10–20% per annum. Protection of the ovary during the critical period of flower opening to fertilization could reduce losses and increase, grain yield and quality. Four fungicides were evaluated over two seasons for ergot control at Cedara. ie. propiconazole, tebuconazole, triadimenol and triadimefon. Desogerme® (1999/2000) and an experimental strobilurin (2000/2001) were evaluated for one season only. Each fungicide was applied at two application rates and times relative to anthesis. No response to Desogerme was recorded. A significant interaction was recorded between fungicides and time of application but this was limited to post-anthesis and multiple applications. Applications prior to the onset of anthesis were least effective while applications at anthesis gave best control. This suggests that translocation to the infection site is via the floret and that floret gaping promotes chemical uptake. Triadimenol and triadimefon were the most effective chemicals. Propiconazole and tebuconazole, which are recommended in Australia, Brazil and USA for ergot control were less effective.

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